Reduction gearing



March l5, 1932. H. F. SCHMIDT REDUCTI 0N GEARING Filed June 30, 1930 z? 14 l5 i ze a `as ll K zo WITNESS l FGJJ'I, lNvENToR Henry Echmid Bf' /,wm

ATTORNEY Patented Mar. 15, 1932 UNlTlE STATES PATENT FFICE` HENRY F. SCHMIDT, 0F LANSDJOWNE, PENNSYLVANIA, ASSIG'NOR TO WESTINGI-IOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA REDUCTION GEARING Application led J une 30,

My invention relates to reduction gearing and it has for an object to piovide apparatus of this character capable of sustaining relatively high tooth'pressures per unit of length with large face-diameter ratios.

`With reduction gearing, where the pinion is supported by suitable bearings and the driving shaft is connected thereto at one end, in operation, the pinion is subject to torsional deflection, which deflection increases toward the coupled end. With a pinion having a pair of toothed portions and supported by a rigid supported construction, the toothed portions deflect torsionally under load so that the part of the load carried by the teeth adj acent to the coupled end tends to concentrate at the end portions of such teeth adjacent to the coupled end, with the result that the pinion is incapable of carrying the load it il? could if the load was distributed oV-e' the toothed portion adjacent to the coupled end. In accordance with my inventioml provide a supporting construction for the pinion N which p rinits of the pinion bending so that inoframe, the floating frame being so conn tion adjacent to the coupled l better contact may be had between the teeth adjacent to the coupled end and the cooperating gear teeth. It is, therefore, a more specic object of my invention to provide supporting apparatus for the pinion of a reduction gear permitting of improved load-carrying capacity on the part of the pinion.

A further object of my invention is toprovide reduction gearing of the floating frame type wherein the pinion is carried by a floatstructed as to deflect or move so as to permit of slight bending `of the pinion providing for better Contact of the teeth of the pinion porend with the cooperating gear teeth.

These and other objects are effected by my invention, as will be apparent from the following description and claims talren in con- I* nection with the accompanying drawings, forming a part of this application, in which:

Fig. 1 a diagrammatic perspective view to indicate principles of my invention;

Fig. 2 is a diagrammatic view indicating n :n appi oximateiy the torsional deflection curve in the pinion;

1930. Serial 110,464,948

Fig. 3 is a detail view of a floating frame and pinion assembly having the bearings in section and showing a modification of the frame to permit of slight bending thereof and the pinion; and,

Fig. l shows a modified form having the floating frame supported by hydraulic pistons, the piston areas being so proportioned as to secure the bending eect.

Referring now to the drawings more in detail, in Fig. 1, I show a gear element of a reduction gear having opposed helically toothed portions 11 and 12 meshing, respectively, with the opposed helically toothed portions 13 and 14 of the pinion member 15. The gear member 10 and the pinion member 15 are of usual construction, the pinion member having end journals 16 and 17 and an intermediate journal 18 cooperating with bearings of a suitable supporting construction hereinafter referred to. The pinion member is made hollow in a well-known manner, the flexible driving shaft 2O from a suitable source of power extending througlithehollow pinion and being connected thereto at the remote end by a suitable coupling 21 permitting of end play of the pinion.

With an ordinary floating frame type Vof support for the journal portions 16, 17 and 18 of the pinion 15, the floating frame would tilt to balance the pressures if the pinion was subject to substantially uniform torsional deflection, that is, if the contact point were on true heli-X; however, as diagrammatically indicated in Figs. 1 and 2, the torsional deflection, instead of being of a uniform character, increased toward the coupled end, with the result that, while the pinion portion 13 may be suitably related to the cooperating gear portion 11 to transmit power, the pinion portion 1d adjacent to the coupled end of the pinion member may be so deflected that the load is carried by a limited portion of the teeth, that is, as shown in Figs. 1 and 2, the load may be restricted to the end of the teeth of the pinion portion 1li adjacent to the coupling in consequence of which the load-carrying capacity of the pinion is reduced. In View of the character of torsional deflection of the pinion resulting in concentration of the y own load.

load on that portion of the pinion member adjacent to the end thereof adjacent to the coupling, I provide a modified form of floating frame construction capable of a limited amount of deformation to better distribute the load between the teeth of the pinion portion 14 and the gear portion 12.

In Fig. 3, I show a floating frame 25 having bearing portions 26, 27 and 2S for the journal portions 16, 17 and 18, the floating frame being supported by a suitable flexible connection, for example, an I-beam section 29. The floating frame is not symmetricaly designed, the portion 30 thereof for the pinion portion 13 being very much stiffer or more rigid than the portion 31 for the pinion portion 14 adjacent to the coupling 21. rihe frame is so designed that the part 3() is comparatively rigid and the entire frame will float due to the I-beain section 29 in order to secure proper tooth contact of the pinion portion 13 and the gear portion 11 under different loads; however, as heretofore pointed out, lwhile the pinion portion 13 may Contact properly with the gear member teeth 11, the pinion portion 14 may be deflected torsionally to such an extent as to restrict its load to the end of the teeth adjacent to the coupling, with the result that, while the teeth of the pinion portion 13 are properly related to the gear member teeth 11, the teeth of the pinion uport-ion 14 will be carrying the load at one end. It is for this reason that the portion 31 of the floating frame is made relatively less rigid permitting' of slight bending thereof and of the pinion so as to permit of more eii'ective contact of the teeth 14 with the teeth 12, with the result that, for a given size of reduction gear, the permissible tooth pressure may be increased.

In order that the compensating action talring place in my improved gearing may be better understood, reference is made to Fig. In this view, the straight lines a and Z) indicate the conditions that would exist if the deflection was uniform from end to end of the pinion. rlhe curve c is the torsion elastic curve for the pinion portion 14 and the curve d is the torsion elastic curve for the pinion 13. The torsional deeetion taking place in the pinion portion 14 is much greater than that taking place in the pinion portion 13 owing to the portion 14 having to transmit the torsional load of portion 14 in addition to its Due to the flexibility permitted by the left hand portion of the frame, allowing the bearing 27 to become out of line with the intermediate bearing 28, the pinion, particularly the left hand portion 14 thereof,

bends or tends to assume a shape indicated by the elastic curve c. IVhile torsional deflection tends to displace the pinion portion 13 with respect to the gear portion 10, this displacement may not be sufficiently great to exceed that of the oil film thickness; and, for

this reason, l show an unsyininetrioal form of traine wherein the portion 3l adjacent to tho coupled end of the pinion is relatively more flexible; however, it is to be understood that my invention comprehends any suitable art' rangement of frame which is constructed and arranged to deflect or bend permitting of bending of the pinion so as to compensate for torsional deflection. As the torsional elastic curves g and c are in opposite direction and represent actions taking place at the same time, the curve g represents the resultant elastic curve for the pinion portion 14 and the latter elastic curve is substantially straight lines. Since the elastic curve (Z does not depart greatly from a straight line and the curve g is substantially a straight line, the design of the pinion and of the frame may be so corelated that these lines are parallel; and, with these lines or curves parallel, the flexible supporting member 29 permits of the frame rotating through a small angle m to bring the teeth of the pinion in contact with the teeth of the gear for the full face width.

In Fig. 4, I show a form of hydraulicallysupported floating frame wherein an intermediate piston 34 and end pistons 35 and 36 support the pinion. Ordinarily, as disclosed in the patents to lhfestingliouse Nos. 1,083,- 337, 1,136,072, 1,136,189 and 1,195,119, the central pistons have about twice the area of the end pistons. To provide for deflection or bending of the pinion to get better load distribution as hereinbefore pointed out, the piston V36 is made of slightly less area than the piston 35 and the piston 34 is made slightly greater in area than twice the area of the piston 35, with the result that the pinion portion 13 is comparatively rigidly supported relatively to the pinion portion 14 whereby the pinion member 15 may bend slightly to permit of better distribution of the load.

While I have shown my invention in two forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon, as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is 1. In reduction gearing, in combination, a gear having right and left hand helicallytoothed portions, a pinion having left and right hand helically-toothed portions meshing with the toothed portions of the gear, a frame for supporting the pinion, a driving member connected to one end of the pinion, said frame and pinion being constructed and arranged to provide for bending or bowing of the frame and pinion portions adjacent to the coupled end of the pinion under load to effect lateral displacement of the pinion teeth adjacent to the coupled end sucient to compensate for torsional displacement of such teeth, whereby with torsional deflection of the pinion under load, the tooth pressure is distributed from end to end of the pinion portion at the coupled end, and means providing for angular movement of the frame transversely of the plane of the pinion and gear axes. Y

2. In reduction gearing, in combination, a

driven gear having right and left hand helically-toothed portions, a pinion having left and right Vhand helically-toothed portions meshing with the toothed portions of the driven gear and having intermediate and terminal journal portions, a driving member connected to one end of the pinion, a frame for the pinion having intermediate and terminal bearing portions fitting said journal 2o portions and the portion of the frame between its intermediate bearing and said coupled end of the pinion being relatively less stift than the other portions, whereby, in operation, such relatively less stii frame portion and the pinion may deflect to secure distribution of load over the portion of the pinion adjacent to the coupled end, and means providing for tilting of the frame transversely of the plane of the pinion and gear aXes.

SU 3. In reduction gearing, in combination, a

driven gear having right and left hand helically-toothed portions, a pinion having left and right hand helically-toothed portions meshing with the toothed portions of the driven gear, and having intermediate and terminal journal portions, a driving member, a slidable coupling between the driving shaft and one end of the pinion, a frame for the pinion having intermediate and terminal bearing portions fitting said journal portions and the portion of the frame between its intermediate bearing and said coupled end of the pinion being relatively less stift than the other portion, whereby, in operation, such relatively less stili frame portion and the pinion may bend or deflect to compensate for torsional deflection of the pinion, and means providing for tilting of the frame transversely of the plane of the pinion and gear axes.

In testimony whereof, I have hereunto subscribed my name this 27th day of June, 1930.

HENRY F. SCHMIDT. 

